My dog is breathing funny and makes noise when she breaths and don't really eat and go to the bathroom?

my dog is a runt and shes 5 lbs and is a jack russel. When she breaths its fast and very d and she sounds like shes wheezing she don't do anything really either and she don't eat much at all or if any and she don't poop very much. I took her to the vet on monday and i was not happy they just checked her (not very well either) and said that would just try worming her and if she don't improve by thursday or friday bring her back in. I'm just so worried that something bads gonna happen can anyone help me. PLEASE i'm desperate!!!!